<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const arr1 = [
        [1, 2, 3], //0(0,1,2)
        [4, 5, 6], //1(0,1,2)
        [7, 8, 9], //2(0,1,2)
      ];
      const arr2 = ["css", "html", "js"];
      console.log("arr1.toString()", arr1.toString());
      console.log("arr2.toString()", arr2.toString());
      // console.log("String(arr1)", String(arr1));
      // console.log("String(arr2)", String(arr2));
    </script>
  </body>
</html>
